Adding Collation Key Analyzer

Hi,

this patch adds the Lucene CollationKeyAnalyzer for locale-sensitive sorting by using java.text.Collator. I know that ICUCollationKey is much preferable https://issues.apache.org/jira/browse/LUCENE-1719 but it could be useful for non-ICU environments, and where performance is not very important. See also my pull request for java.text.Collator based terms facet sorting. It would be nice being able to align hit sorting and terms facet sorting.

Test is included for demonstrating a collation-key based sort.

Cheers, Jörg